Re: [PATCH 2/3] scsi: disable VPD page check on error

["Ewan D. Milne" <emilne@redhat.com>]

On Mon, 2016-06-20 at 08:57 +0200, Hannes Reinecke wrote:
> If we encounter an error during initial VPD page scan we should be
> setting the 'skip_vpd_pages' bit to avoid further accesses.
> Any errors during rescan should be ignored, as we might encounter
> temporary I/O errors during rescan.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
>  drivers/scsi/scsi.c      | 9 ++++++++-
>  drivers/scsi/scsi_priv.h | 2 +-
>  drivers/scsi/scsi_scan.c | 4 ++--
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 1deb6ad..1ff4a0b 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -770,13 +770,14 @@ EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
>  /**
>   * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
>   * @sdev: The device to ask
> + * @first_scan: true if called during initial scan
>   *
>   * Attach the 'Device Identification' VPD page (0x83) and the
>   * 'Unit Serial Number' VPD page (0x80) to a SCSI device
>   * structure. This information can be used to identify the device
>   * uniquely.
>   */
> -void scsi_attach_vpd(struct scsi_device *sdev)
> +void scsi_attach_vpd(struct scsi_device *sdev, bool first_scan)
>  {
>  	int result, i;
>  	int vpd_len = SCSI_VPD_PG_LEN;
> @@ -796,6 +797,8 @@ retry_pg0:
>  	result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
>  	if (result < 0) {
>  		kfree(vpd_buf);
> +		if (first_scan)
> +			sdev->skip_vpd_pages = 1;
>  		return;
>  	}
>  	if (result > vpd_len) {
> @@ -822,6 +825,8 @@ retry_pg80:
>  		result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
>  		if (result < 0) {
>  			kfree(vpd_buf);
> +			if (first_scan)
> +				sdev->skip_vpd_pages = 1;
>  			return;
>  		}
>  		if (result > vpd_len) {
> @@ -851,6 +856,8 @@ retry_pg83:
>  		result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
>  		if (result < 0) {
>  			kfree(vpd_buf);
> +			if (first_scan)
> +				sdev->skip_vpd_pages = 1;
>  			return;
>  		}
>  		if (result > vpd_len) {
> diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
> index 6c3db56..0c4cc6d 100644
> --- a/drivers/scsi/scsi_priv.h
> +++ b/drivers/scsi/scsi_priv.h
> @@ -31,7 +31,7 @@ extern void scsi_exit_hosts(void);
>  /* scsi.c */
>  extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
>  extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
> -void scsi_attach_vpd(struct scsi_device *sdev);
> +void scsi_attach_vpd(struct scsi_device *sdev, bool first_scan);
>  #ifdef CONFIG_SCSI_LOGGING
>  void scsi_log_send(struct scsi_cmnd *cmd);
>  void scsi_log_completion(struct scsi_cmnd *cmd, int disposition);
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index e0a78f5..dcc08ad 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -997,7 +997,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
>  	}
>  
>  	if (sdev->scsi_level >= SCSI_3)
> -		scsi_attach_vpd(sdev);
> +		scsi_attach_vpd(sdev, true);
>  
>  	sdev->max_queue_depth = sdev->queue_depth;
>  
> @@ -1536,7 +1536,7 @@ void scsi_rescan_device(struct device *dev)
>  
>  	device_lock(dev);
>  
> -	scsi_attach_vpd(sdev);
> +	scsi_attach_vpd(sdev, false);
>  
>  	if (sdev->handler && sdev->handler->rescan)
>  		sdev->handler->rescan(sdev);

Reviewed-by: Ewan D. Milne <emilne@redhat.com>